Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare non-read-only, idempotent, non-destructive, closed-world behavior, and the description adds real value on top: it scopes the write to the artifact's own workspace and discloses the 20-pin capacity ceiling plus the 'active markdown' precondition. It stops short of saying what happens at the limit or whether re-pinning reorders.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One sentence with the core action first and the constraints parenthesized after; nothing is wasted. The nested parenthetical makes it slightly denser to parse than a clean two-clause statement would be.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present and full parameter documentation, the description only needed to carry preconditions and limits, which it mostly does. The remaining gap is edge-case behavior (exceeding 20 pins, pinning an already-pinned artifact), likely left to the output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so artifactId, position and why are already fully documented, including the unusual 'accepted and not recorded' note on why. The description adds no parameter-level meaning beyond the schema, so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (pin) and resource (active markdown artifact into its workspace's bounded context), so the operation is unambiguous. It doesn't name the inverse sibling workspace_unpin or explain how pinning differs from e.g. artifact_move, so sibling differentiation is only implicit.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied rather than stated: 'active markdown' hints at a precondition and 'at most 20 pins' hints at capacity, but there is no explicit when-to-use, when-not-to-use, or pointer to workspace_unpin/workspace_view_context. The agent must infer the workflow.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.